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My Hyundai Sonata 2008 smells sour, when the air ventilation is set to external rather than internal.

I always immediately turn it to internal air to avoid the smell.

Where is the ventilation hole/filter and where do I need to clean?

marked as duplicate by DucatiKiller, Pᴀᴜʟsᴛᴇʀ2, George, Fred Wilson, Hᴇʀʙɪᴇ Apr 18 '16 at 2:39

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Your Sonata has a cabin air filter (CAF). You should try to change that out first. More than likely, you have some mildew built up somewhere. The CAF is the first place to start.

  • Do you know generally how CAF are accessible? – ahnbizcad Jul 22 '15 at 5:01

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